1. Field of the Invention
The present invention relates to a guidance information providing apparatus, server apparatus, guidance information providing method, and program for providing guidance information.
2. Description of the Related Art
Recently, a guiding apparatus for guiding a user from a departure place to a destination is beginning to be generally used. Although the most typical example is a car navigation system, a guiding apparatus for a walker is also implemented in some forms.
For example, a guidance service based on user's position information is performed for a portable terminal containing a GPS (Global Positioning System) receiver. Also, a service with which a user can see an information map by explicitly designating a departure place and destination without using any position information as described above is provided by PC software or across the Internet. In these services, a guiding route is automatically generated by searching road network data purchased from a map company.
Unfortunately, network data is unprepared for buildings such as stations and underground malls, so no such guidance services as performed for roads outside such buildings are often performed. A service which presents cars and doors which stop near stairs to a user's portable terminal is performed in some stations. However, this service shows only a limited range by a prepared sentence and hence is unsatisfactory to guide a user over a broad range such as a large station or underground mall having a number of floors.
In addition, photographs showing surface views are posted at some ticket gates of subways. Also, a system which guides a user by pasting or interpolating a plurality of photographs of views of precincts is also developed. However, photographs are temporizing information, so it is difficult for a user to understand the whole image of precincts or a route to the destination.
On the other hand, the web site of a railroad corporation presents a three-dimensional information map of the station precincts drawn by an illustrator. This information map is subjected to three-dimensional deformation processes of, e.g., shifting upper and lower floors and omitting ceilings. Therefore, a user can understand portions which may be hidden in a simple information map. However, this information map drawn by an illustrator is merely a single picture, so a viewpoint position cannot be changed in accordance with a departure place and destination designated by a user.
To solve this problem, it is necessary to accumulate data representing the three dimensional shapes of the precincts of a building in a computer, and dynamically generate an information map in accordance with a departure place and destination designated by a user. However, if the shapes of the precincts are simply three-dimensionally presented, a guiding route is often hidden by obstacles or upper floors. To present a readily understandable information map, therefore, a computer must perform deformation processes similar to those performed by an illustrator.
Many such three-dimensional deformation techniques are described in the conventional patent (Jpn. Pat. Appln. KOKAI Publication No. 2001-273526) of a car navigation system. Examples are a method of extracting an obstacle covering a guiding route and omitting this obstacle or presenting it as a semitransparent object, a method of changing the color or texture of an obstacle, a method of presenting only the contour of an obstacle by using dotted lines, a method of changing the size or height of an obstacle, a method of presenting an obstacle by switching it to an icon or character string, a method of presenting an obstacle by flickering it, and a method of forcedly presenting an obstacle at the back of a route. However, different from roads as objects of car navigation systems, many “layers” are present in the precincts of a building. This makes it difficult to add effective deformation processes only by using the conventional techniques.
Also, the sky over the present location is used as a viewpoint in many car navigation systems. In guidance of the precincts of a building, however, a readily understandable information map can be obtained when a viewpoint from which a user can easily understand ups and downs such as stairs and escalators is selected. Also, when a viewpoint from which a guiding route is not so often obstructed by upper floors is chosen, the amount of deformation processes reduces, so an information map close to an actual view can be obtained. For example, a viewpoint from which the whole three-dimensional shape is clearly seen can be determined in the technique disclosed in P. Vazquez, M. Feixas, M. Sbert, and W. Heidrich, “Viewpoint Selection using Viewpoint Entropy”, VISION, MODELING, AND VISUALIZATION 2001, Stuttgart, Germany, Nov. 21–23, 2001.
Unfortunately, it is difficult for the above-mentioned technique to determine a viewpoint from which ups and downs of a guiding route are readily understandable, or a viewpoint from which a guiding route is not obstructed by upper floors.